Weird Data Loss in pyserial

Question

I'm trying to receive data from a COM port and send it to another COM port with some filter applied on data. but I have a weird problem and I can't find the source of it.

the data contains ZPL commands(zebra printer commands e.g : ^XA^LRY^F0350 and etc) and I want to ignore these commands and only send actual data to printer port.

the problem is when I get data it randomly has data loss! sometimes a few characters and sometimes so many of them ant it is very random!!! for example sometimes for 2 weeks it works fine and sometimes it does not get a single print correctly! at first I think it is because of my filters but then I just completely send data to printer COM without any filter and still have those data losses...

can anyone help me with that? this is the code I write, and how I use it is written at the end of question

receive_ser= serial.Serial()
receive_ser.timeout = None
receive_ser.port = RES_PORT
receive_ser.parity = "N"

printer_ser = serial.Serial(timeout=None)
printer_ser.port = PRINTER_PORT

while True:
    time.sleep(1)
    receive_ser.open()

    bytesToRead = receive_ser.inWaiting()
    data = receive_ser.read(bytesToRead)
    if data != b'':
        printer_ser.open()
        printer_ser.write(data)
    receive_ser.close()
    printer_ser.close()

I turn this .py file into .exe file using pyinstaller in a virtual machine with XP 32 bit OS using this command:

pyinstaller --console --onefile code.py

then I use this .exe file on another PC with Windows XP 32 bit. Is it possible that com srvice of windows not works properly?